As smart phones get loaded with more applications and sharper displays, a phone user is constantly looking for power outlets to recharge his phone. A new development from the UCLA Materials Science department could change that soon. The major user of power in a phone is its display. Some 80-90 per cent of battery drain happens when the phone screen is lit up, which is of course all the time is in use, instead of being in a pocket or a purse.
The phone LCD display is made of two sheets of polarized transparent sheets which sandwich the liquid crystal molecules called pixels. When the phone is in use, a back light gets turned on. These were fluorescent lights earlier but are now, largely LED arrays. The pixels in the display get turned on or off by transistors in the microchips in the phone to allow the back light through to the user’s eye. Only a small part of the back light goes through the pixels and over 75 per cent of the light energy gets absorbed in the polarizing sheets.
The UCLA team led by Professor Yang Yang has come up with an organic photovoltaic polarizer that would convert the light from the back light into electricity to charge the phone battery. In addition, the polarizer would also absorb light from external sources such as sunlight or even indoor lighting to recharge the phone battery. Professor Yang Yang says that this would be the future for display technology for not just phones but also for tablet computers and other electronic devices. Once this technology gets implemented, the only time the phone battery drains is when it is in the pocket or the purse!